Quotes / Legend Fades to Myth

Thom began to recite a tale in High Chant, so flowery it was difficult to recognize the story of Kirukan, the beautiful soldier queen of the Trolloc Wars.
"She had a temper like a boar caught in briars at the best," Birgitte said softly to no one in particular. "Not at all like anyone close by."

The Wheel of Time turns, and Ages come and pass, leaving memories that become legend. Legend fades to myth and even myth is long forgotten when the Age that gave it birth comes again.
The opening of each The Wheel of Time book

When is a legend legend? Why is a myth a myth? How old and disused must a fact be for it to be relegated to the category "Fairy-tale"?
The opening of Dragonflight